Contagious Cancer Found in Dogs

Dan East writes "Scientists in England have gathered definitive evidence that a kind of cancer in dogs, known as Sticker's sarcoma, is contagious. It is spread by tumor cells getting passed from dog to dog through sex or from animals biting or licking each other. Robin Weiss and his colleagues did genetic studies on the tumor cells from 40 dogs with Sticker's sarcoma, collected from five continents, which showed that all the tumor cells are clones of each other. The parent cell probably arose in a domesticated dog of Asian origin — perhaps a husky — hundreds of years ago, and perhaps more than 1,000 years ago. A similarly transmissible cancer has recently been discovered spreading through populations of Tasmanian devils."

Re:How are these Cancer Cells?

[6OOOOO]

Not a doctor, but...

Presumably the oddity is that it's a cancer that behaves as a pathogen--that is, these are rogue dog cells that can jump from dog to dog and continue reproducing as a tumor. It's closest, really, to a parasite, but it's still weirder than that, since it's genetically the same species as its host.

For that matter...

[brunes69]

For that matter, how the hell are these foreign cells growing **whole tumours** in the host without the host's immune system going into complete overdrive?

I mean, it's hard to even transplant a finger in a human without using huge amounts of anti-rejection drugs. How is there a tumor growing inside the dog, with cells that must have a totally different DNA and chromosone pattern? Why is the dog's host system not attacking it?

I mean, part of the whole problem with cancer is that the cells are in fact your own cells, so your body never attacks the infection. But if the cancer is directly contagious than this is not the case at all.

Re:Kill all the dogs!

[k3vlar]

I see that you have never owned a cat or dog. It can be a very rewarding experience, caring for something like that.

Having said that, I agree with your views about how some people seem to value the lives of animals over other human beings.
I saw a commercial once that truly sickened me. They were asking for donations to help save captive bears in an empoverished third world country! I couldn't believe that someone could ask for money to save bears, instead of helping the PEOPLE that couldn't afford enough food. The bears were being held captive to be put on display to earn donations from passers-by, and I thought, "How stupid can this donation organization be! Solve the people problem, and you also solve the bear problem!"

Animal rights groups sicken me sometimes.

Re:For that matter...

[CastrTroy]

I think it has something to do with how close the cells are to the cells of the host. In the case of cancer cells, they contained somewhat damaged DNA, which is the cause of the tumour, yet your body still doesn't attack it, because for some reason or another it doesn't see it as a threat. I think the same thing would apply here. Remember that all breeds of dogs are the same species, even though there's a wide variation of DNA out there to account for all the different breeds. Perhaps dogs have a much larger margin which their body considers safe for presence in their own body due to such a large variation in the genes present in the species.

Re:Damn...I just lost my dog to cancer.

[SlashSquatch]

Condolences.

About the bark park, your dog would not have had it any other way.

Don't worry because:

1. Even though you may point to a risky behavior, this does not imply a cause - effect relationship. Many cancer causing agents will always abound in our environment.

2. I'd choose bark park with a 3/4 life span vs. no fun for a long time and all the other dogs I know agree.

3. A good chunk of the dog population gets the shaft, stuck on a chain, or in a cage and possibly gassed in their prime.

Re:How does it evade the immune system?

[Lazarian]

If this is something unique among cancers, then maybe it's possible to find the mechanism that these foriegn cells are able to integrate themselves in another genetically different organism. Once that could be discovered, maybe this would lead to other approaches in combatting more typical forms of the disease. (I'm not in any medical field, but I've never heard of cancer cells acting like a parasite like these seem to do.)

After just recently losing someone close to cancer, it'd be nice to see some earth-shattering breakthroughs in the field.

Re:Original peer-reviewed Cell link

[stevesliva]

This is worse than prions.

I don't think so. You can quarantine this, and stay away. With prions, you never see them coming. And then your brain melts.

Re:Kill all the dogs!

[Anonymous Coward]

Your post would make sense if people donating money to relieve poverty was mutually exclusive for people donating money for animals. Which it isn't. Don't let logic get in the way of your prejudice though.

p.s. Most bears have their gall-bladders milked and sold for quack medicines. They're far more valuable that way.

Re:It's not even really LIKE a normal cancer...

[digitalhermit]

There's nothing worse than anthropomorphizing your description of cellular mechanics.

Interesting sentiment... Funny how we can talk of "mind" as opposed to "brain" and nobody raises an eyebrow. The idea of consciousness is not that far removed from the idea that DNA is selecting host animals. After all, what is consciousness but the expression of chemical and electrical processes in the brain, similar to the chemical and electrical processes in DNA replication.

Re:tasmanian devil & spreading cancer

[slamb]

fredouil writes:

unfortunately this kind of cancer is not new, here in Australia, the Tasmanian devil are diying and will soon disapear. http://news.nationalgeographic.com/news/2006/02/02 [nationalgeographic.com] 27_060227_tasmanian.html

Here's a question: is it right for us to stop it? This appears to be a natural weakness of Tasmanian devils. The article states:

Pearse noted that inbreeding, and the resulting lack of genetic diversity, may make Tasmanian devils particularly susceptible to this type of infection.

and so an unsuccessful species is dying out, as has happened many times in the past. Now humans are around to stop it (the government is quarantining them; there's even talk of cloning, should the entire population die), but is it beneficial to tamper with nature in this way?

Re:tasmanian devil & spreading cancer

[Anonymous Coward]

Here's a question: is it right for us to stop it? This appears to be a natural weakness of Tasmanian devils.

Humans aren't above evolution. We're part of the process. And one thing evolution has given some of our species is empathy. Another is to determine a system of values to live our lives by. If enough of us determine that the "right thing to do" is to save the Tassie Devil because we're concerned about their plight, then evolution has seen fit to give the Tassie Devil a leg up. There's no right or wrong, just an outcome.

Re:tasmanian devil & spreading cancer

[RsG]

I dislike the arguement that "nature" has any intent or say in the matter. It's too close to a religious belief for my liking; making the natural world or the proccess of evolution into some planning, thinking deity.

Evolution is non-linear. It's a blind proccess based on probability, not some infallable mechanism for ensuring the correct changes occur. Extinction is not fated, nor does it unerringly take only those species who are unsuited to their environment (look at the major mass extinctions in history as proof of this).

And even when natural selection is responsible, why is that "right"? Evolution has no ethics, it simply is. Moreover, even if we start from the assumption that natural selection is right (or is best not interfered with), how can we seperate it out from every other factor involved in an extinction? Death by evolution is like death from old age; it's not a specific cause, it's a general description of what went wrong.

The death of the dodo or the passanger pigeon can argueably be considered a form of evolution; those species unable to cope with a new predator (man) die off. Yet we restrain ourselves from causing other species to go extinct.

We are ourselves unnatural creatures. The natural state of humans is poor health, early death, superstitious ignorance and starvation. We're hunter-gatherers naturally. Do we view our deviation from evolution as wrong?

And even if the tasmanian devils are dying out purely due to non-human factors, what arguement is there against trying to preserve them?

If you want to argue that the only species we have an obligation to preserve are the ones that our own actions have endangered, then that's fine - you're entitled to your own point of view. However, I don't agree with that line of thinking. The fact that we're probably blameless in the fate of the tasmanian devil doesn't mean we have no cause to preserve them.

Re:tasmanian devil & spreading cancer

[deuterium]

There's no right or wrong, just an outcome.

Ahh... a coward after my own heart. I've labored on many occasions to illustrate the fact that whatever people do, it is literally natural. To assume anything else would be placing us in the realm of (again, literally) the supernatural. So whether we destroy the planet, live in wigwams, colonize Mars, or genetically engineer a mouse that glows in the dark, the result is no more unnatural than a beaver damming up a culvert. There is no grand evolultionary, Gaia-mind plan that we run the risk of mucking up. The laws of nature simply play themselves out wordlessly and aimlessly. Isn't that comforting?